Android itself is highly optimized to play media. It's a perfect base to run Kodi. LE isn't the more performant base for Kodi.
On RPi with LE you can use your TV remote, so you don't need to buy that part.
You have to buy the RPi, a case and a PSU. All in all it still could be under 50$.
Here are my instructions to install a power button and a status LED: Instructions.
This will make it work like a commercial box. Don't fear to build it.
Sure you could buy a cheap Android box from China, install the Kodi app, and everything is fine. You really don't need LE as an extra OS.
Problem: You will run into a support problem after a couple of years. Those China boxes have blocked boot loaders, which makes it impossible to install other OS'es. When the China boys decide to stop software updates, then you can throw your box into the dumpster.
That's why we suggest open source software here - you will have support for a long time.
If you have an old PC, the Android X86 project is an option. I'm not sure whether RPi Android is already usable (young project), but I have been tested Android X86 successfully. In combination with the Kodi app this could be all you need.
Tigro :
The only tricky part of an RPi 4B could be Android dual-boot. If you like to switch microSD cards instead, then RPi fits for you.
Just thought I give libreelec a (new) try in the new year and same f*cking problem on both machines.
My RPi 3B+ runs fine with LE. Maybe an add-on problem on your side.
Start to be more practical in 2020, and read your log files.
You will not get a noob-friendly device for that price - you want the best of both worlds. 
If you forget about the price, then the Nvidia Shield TV is the noob-friendly device #1. It runs Kodi (not LE) and Android perfectly.
If it has to be under 50$, then buy a Raspberry Pi 4B (sub-version: as much RAM as you can afford). You can dual-boot Android and LE on it.
What a crazy fix! 
PS: Conclusion: HiFiBerry doesn't test the products they ship. That's bad. 
There is a setting at /storage/.kodi/userdata/guisettings.xml:
<setting id="audiooutput.volumesteps" default="true">20</setting>Reduce 20.
If you really can't get any audio from the card, blame HiFiBerry.They shipped the wrong device, so demand the right one and try again.
PS: If you decide to buy an RPi camera port device, then the add-on "Raspberry Pi Tools" should provide the driver for LE.
You can play around with audio volume / mute by directly editing guisettings.xml (top and bottom of the file).
PS: A little thing you should think about: Usually companies don't upgrade an ordered product without good reason. Maybe they shipped a Pro version, because they know the COAX output is broken, and they hope you only need TOSLINK.
dtoverlay=hifiberry-digi is the right overlay for your device, there is no need for a "Pro" option. Please do a research whether you can use TOSLINK and COAX at the same time (the HiFiBerry company should know). Maybe you can only switch between those two output options.
Have you done a forum search about the projector topic? We already have threads like this.
I have set up an fresh RPi4 box running Raspbian Buster, installed Kodi as well as TVHeadend and now am experimenting with ffmpeg / vlc on that machine to stream as needed. Basic streams with that USB device do work (which I knew already before) but unfortunately so far not the one I need.
Good choice. So it's no LE question anymore. An RPi camera port device will deliver best streaming data to work with. So don't fall in love with your USB camera too much.
Can you please validate if this command correct/sufficient to enforce full HD?
echo 1080p60hz > /storage/.kodi/userdata/disp_cap | systemctl restart kodi
I only have an RPi, so I don't have a disp_cap file. Maybe blueribb can do the test, because he is an Intel NUC owner.
Display MoreLibreELEC:~ # tail /sys/class/drm/*/status
==> /sys/class/drm/card0-DP-1/status <==
connected
==> /sys/class/drm/card0-DP-2/status <==
disconnected
==> /sys/class/drm/card0-HDMI-A-1/status <==
disconnected
==> /sys/class/drm/card0-HDMI-A-2/status <==
disconnected
Maybe you have some special setting at your TV, and you can switch between HDMI and Display Port mode.
How would I plug Raspbian USB camera drivers (which ones?) into LE without building it from source? I would really be glad if you could provide a hint.
I'm not familiar with camera drivers on Linux. On a working Linux (like Raspbian) you could use the lsmod command to list all loaded driver modules. Then identify the modules for your camera. On a non-working Linux (like LE) you can try to load those driver modules by insmod <module_name>. If you get a "not found" error while trying to load the modules, then my theory will be proofed.
Unfortunately there is no way to install new drivers modules on LE without compiling from source. Maybe driver modules for the RPi camera port are available by default on LE.
Have removed almost everything and put tvservice -p im autostart.sh and it keeps working at 1080p.
If it's solved now, you can mark the thread that way.
